A major FaceTime bug which lets you hear the audio coming through the phone of the person you’ve called before they’ve even answered has been discovered in a viral tweet today.

Much to the concern of iPhone users, the significant privacy issue essentially means you can listen in on any iOS user before they’ve accepted or rejected your call. There is no indication on the recipient’s side that their audio can be heard by the caller.

Now you can answer for yourself on FaceTime even if they don’t answer???? #Apple explain this.. pic.twitter.com/gr8llRKZxJ

— Benji Mobb™ (@BmManski) January 28, 2019

The glitch is believed to affect any pair of iOS devices running iOS 12.1 or later, and can be tested as below:

Until Apple fixes the bug, the only way to avoid your conversations from being overheard when your phone is ringing with a FaceTime request is by disabling FaceTime altogether in iOS Settings.

Tech website 9to5mac, in a series of recreations of the glitch, has also found that it is possible to see video of the person you’re calling without their permission.

“What we have also found is that if the person presses the Power button from the lock screen, their video is also sent to the caller – unbeknownst to them,” the website posted.

“In this situation, the receiver can now hear your own audio, but they do not know they are transmitting their audio and video back to you. From their perspective, all they can see is accept and decline.”

I just replicated the issue – on top of that, if you “join” the call using your invitation on another device (in this case another iPhone) you also get video!! Even though the call is still ringing / not answered on the destination device.

— Jessassin (@Jessassin) January 29, 2019

They also replicated the problem with an iPhone calling a Mac. They found that by default, the Mac rings for longer than a phone so it can act as a listening device for a longer duration.

Apple says the issue will be fixed in a software update later this week.